Draft: Implementation of needed MC event model and detector elements for TORCH

Infrastructure for TORCH detector simulation. At this moment it cares about MC event class needed for Gauss application and TORCH detector elements etc. Elements included are:

• MC hit for optical photons with minimum required information. Should be generic in order to be reusable by other detectors with optical photons.
• MC extended hit adding additional information useful for detailed studies but not required for standard simulation. Split of the information between two should be reviewed. By default, TES location for extended hits is declared, but hits are created only when explicitly activated. Also for this, idea is to have something generic for all relevant detectors.
• Corresponding packers and unpackers for MC hits for optical photons.
• Setup TORCH hits outputs if TORCH is activated.
• Detector element for TORCH.
• Class IDs have to be reviewed, currently they are randomly chosen to be unique but without much logic.